RU2762134C1 - Adhesive composition and method for production thereof - Google Patents

Abstract

FIELD: adhesives.

SUBSTANCE: invention can be used for manufacturing a water-removable adhesive. The adhesive composition comprises lysine, alpha-ketoglutaric acid, and water. Lysine and alpha-ketoglutaric acid are therein present in the form of an aqueous salt solution and do not form precipitation. The molar ratio of lysine and alpha-ketoglutaric acid lies within the range from 1.7:1 to 1:3. Also proposed are a method for producing an adhesive composition and an adhesive product containing said adhesive composition.

EFFECT: improved adhesion of the water-removable adhesive composition.

8 cl, 11 tbl, 7 ex

Description

FIELD OF TECHNOLOGY

[0001] One or more embodiments relate to a novel adhesive composition and a method for its preparation.

LEVEL OF TECHNOLOGY

[0002] As raw materials for adhesives, a petroleum-derived monomer and an oil solvent are commonly used. Petroleum-derived monomers and adhesives made from such monomers can pose problems such as reduced production due to limited oil reserves, the formation of endocrine disrupting chemicals in the production of monomers and adhesives, and toxicity due to the disposal of monomers and adhesives. In particular, since petroleum-derived organic solvents are used in traditional adhesives manufacturing processes to improve the adhesive strength of the manufactured adhesives, workers' health is at risk and concerns about environmental pollution are increasing. In addition, since most adhesives contain monomer units covalently bonded to each other, natural degradation of the adhesives is difficult and undecomposed polymers can cause environmental pollution. Therefore, various water-removable adhesives have been developed to effectively remove adhesives from materials to be bonded. Effective removal of traditional water-removable adhesives from materials and substrates to be bonded requires high temperatures and alkaline conditions, and additional energy must be used. In addition, secondary environmental pollution can be caused by recycling of the adhesives raw material molecules when the adhesives attached to the materials or substrates to be bonded are removed with water.

DESCRIPTION OF IMPLEMENTATION OPTIONS

TECHNICAL PROBLEM

[0003] One or more embodiments include an adhesive composition.

[0004] One or more embodiments include a method for preparing an adhesive composition.

SOLUTION

[0005] Hereinafter, an adhesive composition and a method for producing the same in accordance with an embodiment will be described in more detail.

[0006] Provided is an adhesive composition comprising lysine, alpha-ketoglutaric acid and water, wherein lysine and a-ketoglutaric acid are present in the form of an aqueous salt solution and do not form precipitates in the adhesive composition.

[0007] Throughout the description, the term "adhesion" refers to the phenomenon in which two objects (excluding gases) are located in close proximity, and it takes effort (or work) to separate the two objects by subsequently stretching them. If necessary, some adhesion materials can cure after a predetermined period of time after being applied to a substrate. When such an adhesive is removed from the substrate, irreversible physical deterioration can occur. In addition, the term "adhesion" can encompass "viscoelasticity" in which a force is required to release the adhesive from the substrate to cause viscoelastic deformation. The viscoelastic adhesive composition can be stored and distributed after pretreatment prior to application to a substrate. Thus, its adhesion forces can be maintained after a certain period of time. Examples of adhesive products obtained by applying the adhesive composition to a substrate and drying the composition may include oriented polypropylene (OPP) -based tags and tapes. Through the use of adhesive properties, it can be possible to reversibly attach and detach. By applying the adhesive composition to a substrate and drying the composition, an adhesive layer with viscoelastic properties is formed on the substrate.

[0008] Here, viscosity refers to the property of slowing down the flow of a substance due to internal friction between molecules. In this case, friction is the force that prevents the difference in the distribution of flow rates. Adhesion and viscosity are independent properties. A high viscosity composition can have very low adhesion and a low viscosity composition can have high adhesion.

[0009] Throughout the description, precipitates can include the water-insoluble salt AB (s) formed by chemical changes in an aqueous solution of lysine A (aq) and an aqueous solution of alpha-ketoglutaric acid B (aq), as shown in the reaction scheme 1 below, solid lysine A (s) or solid alpha-ketoglutaric B (s) precipitated in an aqueous solution of lysine A (aq) or an aqueous solution of alpha-ketoglutaric B (aq) as shown in reaction scheme 2 below, and the solid substance lysine A (s) or alpha-ketoglutaric B (s), which did not dissolve in the solvent, but remained in an undissolved state.

[0010] Reaction Scheme 1:

[0011] A (aq) + B (aq) -> AB (tv).

[0012] Reaction Scheme 2:

[0013] A (aq) -> A (tv).

[0014] Also used herein, "precipitation" can refer to deposits formed before the adhesive composition is applied to a substrate or material to be bonded, or during storage or distribution of the adhesive composition.

[0015] As used herein, the term "lysine" refers to a basic α-amino acid, and lysine can be obtained by biosynthesis from oxaloacetic acid in the lysine biosynthetic pathway or by chemical synthesis.

[0016] Lysine may include one type of lysine or a mixture of at least two types of lysine.

[0017] Lysine may include at least one of L-lysine represented by formula 1 below, D-lysine represented by formula 2 below, and salts thereof.

[0018] Formula 1

[0019]

[0020] Formula 2

[0021]

[0022] Lysine salts may include, for example, lysine sulfate, lysine acetate, lysine monohydrochloride, lysine dihydrochloride, lysine monohydrate, lysine acetylsalicylate, lysine phosphate, lysine diphosphate, or a mixture or combination thereof. Such lysine salts can be converted to free forms of lysine.

[0023] Methods for converting lysine salts into free forms of lysine are well known in the art. You can also use commercially available raw materials containing lysine. For example, lysine can be D-lysine, L-lysine and / or DL-lysine. Since their physicochemical properties are the same or similar, the characteristics of the adhesive compositions containing them are also the same or similar, thereby being included within the scope of the present invention. In accordance with an embodiment, lysine can be obtained from a fermentation broth.

[0024] Alpha-ketoglutaric acid is an organic acid represented by Formula 3 below.

[0025] Formula 3

[0026]

[0027] In the adhesive composition, lysine and alpha-ketoglutaric acid may be present in the form of an aqueous salt solution. In particular, although lysine, alpha-ketoglutaric acid, and water are miscible, lysine and alpha-ketoglutaric acid can be present in the form of an aqueous salt solution without forming a covalent compound or insoluble salt. In accordance with the present invention, alpha-ketoglutaric acid is not present in the adhesive composition in a water-insoluble form.

[0028] In the adhesive composition according to the embodiment, the respective contents of lysine, alpha-ketoglutaric acid and water can be adjusted such that lysine and alpha-ketoglutaric acid do not form crystals or precipitates. When the adhesive composition is maintained in a liquid phase without the formation of crystals or precipitates, then the adhesive composition can exhibit excellent adhesion and can be uniformly applied to a substrate.

[0029] The molar ratio of lysine to alpha-ketoglutaric acid in the mixture can range from 1.7: 1 to 1: 3. For example, the molar ratio of lysine to alpha-ketoglutaric acid in the mixture can range from 1.6: 1 to 1: 2, from 1.5: 1 to 1: 2, from 1.4: 1 to 1: 2, from 1.3: 1: to 1: 1.5 or 1.2: 1 to 1: 1.5. When the ratio of lysine content to alpha-ketoglutaric acid content is greater or less than the ranges described above, precipitates are formed in the composition, resulting in decreased adhesion or deterioration in storage stability or aging resistance.

[0030] The solids content of the adhesive composition may be 70 parts by weight or less, for example, in the range of 0.1 parts by weight to 70 parts by weight, 1 part by weight to 70 parts by weight, or 10 parts by weight up to 70 parts by weight based on 100 parts by weight of the composition. When the solids content is within the ranges described above, the adhesive composition can be easily applied to the substrate. When the solids content exceeds 70 parts by weight, the composition cannot be used as an adhesive composition due to the formation of deposits in the adhesive composition. Although the solids content is reduced, the adhesive composition does not precipitate or lose its adhesion strength. Thus, the solids content can be adjusted from 0.1 parts by weight to 10 parts by weight.

[0031] Alpha-ketoglutaric acid and lysine can be contained in the adhesive composition as active ingredients. The sum of the alpha-ketoglutaric acid content and the lysine content can range from 60 parts by weight to 100 parts by weight, from 70 parts by weight to 99 parts by weight, from 80 parts by weight to 98 parts by weight, or from 85 parts by weight. up to 97 parts by weight based on 100 parts by weight of the solids content of the adhesive composition.

[0032] The adhesive composition according to an embodiment may further comprise an organic acid selected from citric acid, itaconic acid, oxaloacetic acid and malic acid as a minor component in addition to lysine and alpha-ketoglutaric acid. The content of the organic acid may be in the range of 0.1 parts by weight to 10 parts by weight, for example, 0.1 parts by weight to 5 parts by weight, based on 100 parts by weight of alpha-ketoglutaric acid. When the adhesive composition further contains an organic acid selected from citric acid, itaconic acid, oxaloacetic acid and malic acid as described above, the adhesive strength of the adhesive composition can be easily adjusted for different applications.

[0033] In accordance with another aspect of the present invention, alpha-ketoglutaric acid and lysine may be included as a condensate containing alpha-ketoglutaric acid and lysine as units. For example, the condensate can be a dimer, trimer, or oligomer. The condensate content may be 20 parts by weight or less, 10 parts by weight or less, or 1 part by weight or less, including 0, based on 100 parts by weight of the sum of the lysine content and the alpha-ketoglutaric acid content. If the condensate content exceeds the ranges described above, the adhesive strength of the adhesive composition may decrease or the adhesive composition may not be maintained in the liquid phase.

[0034] The effects of the adhesive composition according to the embodiment with respect to the adhesion described above will be given below. They should not be construed as limited to the effects described below, and they can also be construed as other effects in the absence of scientific controversy.

[0035] Lysine has two amino groups and alpha-ketoglutaric acid has two carbonyl groups. The lone electron pair of oxygen of the carbonyl group of alpha-ketoglutaric acid can interact with the hydrogen of the amino group of lysine through ionic hydrogen bonds.

[0036] Thus, when the components of the adhesive composition according to the embodiment are analyzed by liquid chromatography or the like, lysine and alpha-ketoglutaric acid can be identified as raw materials. Thus, it can be confirmed that lysine and alpha-ketoglutaric acid are ionically hydrogen bonded in the adhesive composition and are present in the form of an aqueous salt solution, respectively. In an adhesive composition according to an embodiment, lysine and alpha-ketoglutaric acid can have excellent adhesion properties while being maintained in a liquid phase at room temperature (25 ° C.) without crystals (solid state) or precipitation.

[0037] The adhesive composition according to the present invention can be removed with water. Thus, when the adhesive composition according to the present invention is used as an adhesive, then the water will release the adhesive from the substrate or adhesive to which the adhesive is applied and thereby easily peel off and remove therefrom. In particular, the adhesive applied to the substrate or material to be bonded can be peeled off in 12 hours, specifically in 6 hours, or more specifically in 2 hours, at room temperature (25 ° C) while stirring or rinsing with water. The adhesive composition in accordance with an embodiment is easily separated by the action of water, and the separated components also do not have a negative impact on the environment, since they are not harmful to living organisms and the environment.

[0038] The adhesive composition according to the present invention may further comprise at least one alcoholic solvent selected from a primary alcohol, a polyhydric alcohol, a diol, and a triol. When additional solvent is added to the adhesive composition, the drying rate of the adhesive composition can be increased and the workability of the adhesive composition can be improved.

[0039] The weight ratio of deionized water to alcohol when mixed in an adhesive composition according to an embodiment may range from 1: 1 to 10: 0. More specifically, the weight ratio of deionized water to alcohol when mixed in the adhesive composition can range from 1: 1 to 10: 1, 1: 1 to 5: 1, or 1: 1 to 3: 2. Since the alcohol content in the adhesive composition is increased, the adhesive composition dries more efficiently and is easier to apply, which leads to an increase in peel strength. However, when the alcohol content of the adhesive composition is 1.5 times or more than the deionized water content, phase separation may occur in the adhesive composition.

[0040] The alcoholic solvent can be a monohydric alcohol, a polyhydric alcohol, an unsaturated aliphatic alcohol, an alicyclic alcohol, or any mixture thereof. The monohydric alcohol may include at least one alcohol selected from methanol, ethanol, propan-2-ol, butan-1-ol, pentan-1-ol, and hexadecan-1-ol. The polyhydric alcohol may include at least one alcohol selected from ethane-1,2-diol, propane-1,2-diol, propane-1,2,3-triol, butane-1,3-diol, butane-1, 2,3,4-tetraol, pentane-1,2,3,4,5-pentol, hexane-1,2,3,4,5,6-hexole and heptane-1,2,3,4,5, 6,7-heptol.

[0041] The unsaturated aliphatic alcohol, for example, may include at least one alcohol selected from prop-2-en-1-ol, 3,7-dimethylocta-2,6-diene-1-ol, and prop-2-yne -1-ol.

[0042] The alicyclic alcohol may include at least one alcohol selected from cyclohexane-1,2,3,4,5,6-hexole and 2- (2-propyl) -5-methylcyclohexan-1-ol.

[0043] The pH of the adhesive composition can range from 2 to 11, in particular from 2 to 9.5, and more particularly from 2 to 8.5. An adhesive composition with a pH within the ranges described above is excellent in storage stability and aging resistance without changing composition or quality even after long-term storage. The adhesive composition can exhibit excellent adhesion without precipitation when used not only immediately after preparation but also after long-term storage.

[0044] Mixing lysine, alpha-ketoglutaric acid and water can be carried out by adding alpha-ketoglutaric acid to an aqueous solution of lysine or by simultaneously mixing lysine, alpha-ketoglutaric acid and water.

[0045] In particular, the adhesive composition may be a composition in which no precipitation forms after storage or distribution for 14 days or more. For example, since the adhesive composition is stable, its physical properties can be maintained after storage for 14 days or more, for example 12 months or more. In addition, the ambient temperature in which the adhesive composition is stored can be in the range from -18 ° C or higher to less than 40 ° C, in particular in the range from -18 ° C to 35 ° C, from 0 ° C to 60 ° C or from 20 ° C to 35 ° C. Although the adhesive composition is stored at low or high temperatures, temperature may not affect the composition and quality of the adhesive composition, provided that the ambient temperature at which the adhesive composition is used is room temperature. For example, when the adhesive composition is stored at a low temperature, the adhesive composition can be used after being kept at room temperature for a predetermined time before use.

[0046] In accordance with another aspect of the present invention, there is provided a method for preparing an adhesive composition comprising mixing lysine, alpha-ketoglutaric acid and water and stirring the mixture at a temperature of less than 40 ° C.

[0047] When mixing lysine, alpha-ketoglutaric acid and water and stirring the mixture at a temperature of less than 40 ° C is carried out outside the temperature range, reaction by-products, impurities and the like may be produced. In some cases, it can be difficult to obtain an adhesive composition with the required degree of adhesion.

[0048] Stirring the mixture at a temperature of less than 40 ° C can be carried out, for example, at a temperature of from 0 ° C to 40 ° C. More specifically, this process can be carried out at temperatures from 0 ° C or higher to less than 40 ° C, from 0 ° C to 30 ° C, or from 0 ° C to 25 ° C.

[0049] For example, stirring the mixture at less than 40 ° C may include: i) a first mixing step and stirring at a temperature of 0 ° C or higher to less than 40 ° C, 0 ° C to 30 ° C, or 0 ° C to 25 ° C and ii) a second stage of cooling to room temperature (from 20 ° C to 30 ° C).

[0050] Mixing lysine, alpha-ketoglutaric acid and water can be carried out by adding alpha-ketoglutaric acid to an aqueous solution of lysine or by simultaneously mixing lysine, alpha-ketoglutaric acid and water.

[0051] The method may also include removing water and solvent by concentration under reduced pressure to control the solids content of the adhesive composition within a predetermined range.

[0052] In accordance with another aspect of the present invention, there is provided an adhesive product comprising an adhesive composition applied to a substrate. The adhesive product may contain a substrate and an adhesive layer obtained by applying the adhesive composition to the substrate and drying the adhesive composition. The solvent included in the composition can be removed by drying. Drying can be carried out at temperatures between 25 ° C and 45 ° C.

[0053] The substrate can be any adhesive commonly used in the art to which the adhesive composition can be applied. The substrate can be, for example, a glass substrate, a stainless steel substrate (SUS), or a polymer film. As the polymer film, for example, a film based on polyolefins such as polyethylene, polypropylene, ethylene / propylene copolymer, polybutene-1, ethylene / vinyl acetate copolymer, or a polyethylene / styrene butadiene rubber blend or polyvinyl chloride film can be used. In addition, a plastic material such as polyethylene terephthalate, polycarbonate and poly (methyl methacrylate), or a thermoplastic elastomer such as polyurethane and a polyamide-polyol copolymer, and any mixture thereof, can also be used.

[0054] The substrate may have a roughened surface to improve the adhesion strength between the substrate and the adhesive composition. In another embodiment, the surface of the substrate can be treated to render it hydrophilic. By using a substrate treated to render hydrophilic properties, the adhesive composition can be more evenly applied to the hydrophilic substrate, thereby improving the film-forming property.

[0055] When a glass substrate is used as the substrate, the adhesive composition can be more uniformly applied to the hydrophilic glass, and thus, the film-forming property of the adhesive composition can be improved. When the SUS substrate is used as the substrate, the alpha-ketoglutaric acid contained in the adhesive composition induces interactions with SUS, and thus adhesion between the substrate and the adhesive formed from the adhesive composition is improved.

[0056] In accordance with another aspect of the present invention, there is provided a method of attaching a first substrate to a second substrate, comprising applying an adhesive composition to a first substrate to bond the adhesive composition to the first substrate; and bringing the first substrate to which the adhesive composition is bound into contact with the second substrate to adhere the first substrate to the second substrate.

[0057] Each of the first substrate and the second substrate may be independently selected without limitation from glass, stainless steel, polymer film, metal, plastic, paper, fiber, and soil. For example, the first substrate can be formed from the same material as the second substrate.

[0058] The adhesive composition or adhesive product according to the embodiment can be used as the water-removable adhesive in the production of adhesive tapes, label sheets, spray-type adhesives, dust collectors and the like, and can be easily removed from the bonded material using water without damaging the bonded material, and the packaging materials can be easily recycled. In addition, when the adhesive composition or adhesive product is applied to pesticides and seeds, their range of applications can be expanded due to their water removal properties. The water-removable adhesive of the present invention can be manufactured at a lower cost, can be easier to handle, and has improved processability and cleanliness compared to traditional organic solvent-based adhesives.

[0059] A biological monomer can be selected as a starting material for the adhesive composition according to the present invention. Since the biological monomer can be used by living organisms, environmental pollution caused by oil-derived monomers, polymers or oligomers formed by separating the adhesive using water can be prevented in advance. Structures such as adhesive tapes and label sheets obtained using the adhesive composition of the present invention as water-removable adhesives exhibit improved mechanical strength such as tensile strength and peel strength.

[0060] According to another embodiment, the adhesive composition or adhesive product may further comprise at least one additive selected from a reactive diluent, emulsifier, tackifier, plasticizer, filler, anti-aging agent, curing accelerator, flame retardant, coagulant, surface -active agent, thickener, UV protection, elastomer, pigment, colorant, flavoring agent, antistatic agent, anti-caking agent, friction reducer, inorganic filler, stirring agent, stabilizer, modifying resin, binder , leveling agent, fluorescent brightening agent, dispersing agent, heat stabilizer, photo stabilizer, UV absorber, wax, moisturizer, antioxidant, preservative and lubricant. Although the total amount of additives is not particularly limited, different additives can be contained in different weight ranges according to the application. The additives described above can be used in amounts commonly used in the art, respectively.

[0061] A reactive diluent is a diluent that helps each component of the composition uniformly coat the article to which the composition is applied, and may include at least one diluent selected from n-butyl glycidyl ether, aliphatic glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, o-cresylglycidyl ether, nonylphenylglycidyl ether, p-tert-butylphenylglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentylglycidyl ether, 1,4-cyclohexanedimethylol diglycidyl ether diethylene glycol diglycidyl ether, resorcinol diglycidyl ether, hydrogenated bisphenol A-glycidyl ether, trimethylol propentriglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, pentaerythyrythritol polyglycidyl ether idyl ether of castor oil, sorbitol polyglycidyl ether, glycidyl ether of neodecanoic acid, diglycidyl-1,2-cyclohexanedicarboxylate, diglycidyl-o-phthalate, N, N-diglycidylamine, N, N-diglycidyl-o-toluidene-triglycidine-triglycidine , tetraglycidyldiaminodiphenylmethane, triglycidyl isocyanate, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polypropylene glycidyldiglycidyl ether and triethylolpropentriglycidyl ether.

[0062] The emulsifier may include, for example, at least one emulsifier selected from a polyoxyethylene-polyoxypropylene copolymer, a polyoxyethylene-polyoctylphenyl ether copolymer, and sodium dodecylbenzenesulfide.

[0063] The tackifier can be, for example, rosin and its modified products (for example, rosin, hydrogenated rosin, polymerized rosin, maleated rosin, rosin-glycerin and rosin-modified phenolic resin), terpene-based resin (for example, terpene resin, terpene phenol resin, terpene styrene resin and terpene phenol resin), petroleum resin (for example, C5 petroleum resin, C9 resin, bicyclic nonadiene petroleum resin, hydrogenated petroleum resin, phenyl phenol resin) cashew oil modified resin, tall oil modified phenolic resin, rubber, resin emulsion (e.g. rosin emulsion, TPR resin aqueous emulsion, 2402 resin emulsion and petroleum resin emulsion), cumarone-indene resin, and the like.

[0064] To improve process fluidity or elongation, a plasticizer may be included in the composition. The plasticizer can also improve the functions of the composition such as electrical insulation, adhesion, cold strength, lightfastness, oil resistance, saponification resistance, fire resistance, thermal stability, ease of workability (intramolecular activity), activity (intermolecular activity), and non-toxicity.

[0065] A plasticizer for improving cold strength can be dioctyl adipate (DOA), dioctyl azelate (DOZ), dioctyl sebacate (DOS), Flexol TOF (UCC company), polyethylene glycol ester, and the like. The plasticizer for improving heat resistance (non-volatility) and the absence of transmutation can be a polymer mixture such as polyester and nitrile butadiene rubber (NBR), trimellite ester, pentaerythritol ester and the like. The plasticizer for improving lightfastness can be DOP, DOA, DOS, polyester, epoxidized soybean oil (ESBO), and the like.

[0066] The plasticizer to improve oil resistance can be Phosflex aromatic phosphate ester (product name: TPP, TCP, 112 (CDP) and 179A (TXP)), polyester, NBR, etc., and a plasticizer to improve resistance to saponification can be TCP, ESBO, polyester, etc.

[0067] The flame retardant plasticizer may be a phosphate such as TCP and TXP, chlorinated paraffin, chlorinated alkyl stearate, NBR, and the like, and the thermal stability plasticizer may be ESBO, DOZ, DOS, DOP, polyethylene glycol ester etc.

[0068] The plasticizer to increase ease of workability can be DOA, BBP, TOF, TCP, octyldiphenyl phosphate, and the like, and the plasticizer to improve activity can be DOZ, DOS, dibasic lead phosphate (DLP), ESBO, polyethylene glycol ester etc.

[0069] The non-toxic plasticizer can be BPBG, octyldiphenyl phosphate, ESBO, citric acid ester, NBR, and the like.

[0070] More specifically, examples of the plasticizer may include dibutyl phthalate (DBP), dihexyl phthalate (DHP), di-2-ethylhexyl phthalate (DOP), di-n-octyl phthalate (DnOP), diisooctyl phthalate (DIOP), didecyl phthalate (DDP), diacyl phthalate DIDP), mixed phthalate of higher C8-C10 alcohols, butylbenzyl phthalate (BBP), dioctyl adipate (DOA), dioctyl azelate (DOZ), dioctyl sebacate (DOS), tricresyl phosphate (TCP), trixylenyl phosphate (TXP), mono-octylphosphate (TOF), aroma oil, polybutene or paraffin.

[0071] A thickener as used herein may be, for example, alginin, alginic acid, sodium alginate, guar gum, xanthan gum, collagen, alginate, gelatin, furcellaran, agar, carrageenan, casein, locust bean gum, pectin, polyethylene oxide , polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, etc.

[0072] The surfactant can be any surfactant commonly used in the art. For example, the surfactant may be a C8-C18 alkyl sulfate, a C8-C18 alkyl ether sulfate, or a C8-C18 alkyl aryl ether sulfate containing ethylene oxide or propylene oxide units and a hydrophobic group, a C8-C18 alkyl sulfonate, an alkyl aryl sulfonate, an ester or a polyhydric acid ester or sulfonate C8-C40 alkyl polyglycol ether or C8-C40 alkylaryl polyglycol ether containing ethylene oxide units and the like. For example, sodium dodecyl sulfate (SDS), sodium silicate and the like can be used for this.

[0073] A filler is added to increase the strength, durability and processability of the composition. Examples of filler may include calcium carbonate, talc, ceramics, silica, dolomite, clay, titanium white, zinc oxide, carbon (prevents shrinkage or blocking), potassium carbonate, titanium oxide, liquid polysulfide polymer, volatile diluent, magnesium oxide, and refined petroleum ...

[0074] The curing accelerator can be, for example, dibutyltin dilaurinate, JCS-50 (Johoku Chemical Company Ltd.) or Formate TK-1 (Mitsui Chemical Polyurethane Corporation). The antioxidant can be, for example, dibutylhydroxytoluene (BHT), IRGANOX® 1010, IRGANOX® 1035FF, or IRGANOX® 565 (all manufactured by Chiba Specialty Chemicals).

[0075] The antistatic agent is not particularly limited, and examples thereof may include 1-hexyl-4-methylpyridinium hexafluorophosphate, dodecylpyridinium hexafluorophosphate, fluorinated organometallic compound (for example, HQ-115 from 3M Company), alkali metal salt (for example, NaPF ₆ , NaSbF ₆ , KPF ₆ and KSbF ₆ ), conductive polymer (e.g. polythiophene (PEDOT from Bayer), polyaniline and polypyrrole), metal oxide (e.g. indium doped tin oxide (ITO), antimony doped tin oxide (ATO), tin oxide , zinc oxide, antimony oxide and indium oxide), quaternary ammonium salt (eg, acrylamide-diallyldimethylammonium chloride copolymer solution from Sigma-Aldrich), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM] [PF ₆ ], bis (trifluoro) 1-butyl-3- (2-hydroxyethyl) imidazolium imide [BHEIM] [NTf ₂ ] and tetrabutylmethylammonium bis (trifluoromethanesulfonyl) imide [TBMA] [NTf ₂ ], which can be used alone or in combination of at least two of them.

[0076] Elastomer refers to a rubber or polymer with elastomeric properties, and it can be, for example, ethylene-vinyl acetate copolymer, acrylic rubber, natural rubber, isoprene rubber, styrene-butadiene rubber, chloroprene rubber, butyl rubber, ethylene-propylene-copolymer ethylene rubber -butylene-styrene or acrylonitrile-butadiene copolymer.

[0077] The stabilizer stabilizes the adhesion strength of the adhesive composition and the like, and examples thereof may include a polyol and a polyamine. For example, for this you can use at least one stabilizer selected from alkylene glycol, dialkylene glycol, benzenediol, benzene triol, amino alcohol, amino alcohol, arabitol, mannitol, isomalt, glycerin, xylitol, sorbitol, maltitol, erythritol, ribitol, dulcitol, lactic acid, iditol, polyglycitol, alkylenediamine, alkenylenediamine, phenylenediamine and n-aminoalkylalkane diamine.

[0078] The fluorescent brightening agent can be a benzoxazole compound, a benzotriazole compound, a benzoimidazole compound, and the like.

[0079] The pigment can be a natural or synthetic pigment, or an inorganic or organic pigment if classified according to another criterion.

[0080] The flavoring agent can be, for example, without limitation, peppermint oil, spearmint oil, carvone, or menthol, used alone or in combination.

[0081] The flame retardant can be melamine cyanurate, magnesium hydroxide, agalmatolite, zeolite, sodium silicate, aluminum hydroxide, antimony (antimony trioxide) and the like. An additive to improve water resistance can be glyoxal.

[0082] Examples of the modifying resin may include a polyol resin, a phenolic resin, an acrylic resin, a polyester resin, a polyolefin resin, an epoxy resin, and an epoxidized polybutadiene resin.

[0083] The binder can improve adhesion and reliability of adhesion between the adhesive composition and the packaging material. By adding a binder, the reliability of adhesion can be improved when the composition is stored for a long period of time at high temperatures and / or high humidity. Examples of the binder may include a silane compound such as γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-metakriloksipropiltrietoksisilan, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 3-Isocyanatopropyltriethoxysilane, γ-acetoacetatopropyltrimethoxysilane, γ-acetoacetatopropyltriethoxysilane, β-cyanoacetyltriethoxysilane, β-cyanoacetyltriethoxysilane, and acetoxyacetotrimethoxysilane.

[0084] The stirring aid can be an aromatic hydrocarbon resin.

[0085]

[0086] The anti-aging agent can be N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine.

[0087] The humectant can be, for example, sugar, glycerin, aqueous sorbitol, or aqueous amorphous sorbitol, alone or in combination.

[0088] The UV absorber can be ethylhexylmethoxycinnamate (eg, 2-ethylhexyl-4-methoxycinnamate), ethylhexylsalicylate, 4-methylbenzylidene camphor, isoamyl-p-methoxycinnamate, octocrylene, phenylbenzimidazole sulfate-sulfate-acidic acid, homoxisylactic acid salicylate, PABA, ethylhexyldimethyl-PABA, glyceryl-PABA, etc. These compounds can be used singly or in combination of at least two of them.

[0089] In addition to the additives described above, the adhesive composition or adhesive product according to the present invention may further comprise additives disclosed in US4959412, CA1278132, US6777465, WO2007-120653, US2003-0064178, US7306844, US7939145, WO2011-136568, WO2010- 071298, Korean Patent Application Publication No. 2016-0095132, Japanese Patent Application Publication No. 5959867, and Korean Patent Publication No. 989942, which are hereby incorporated by reference.

[0090] The adhesive composition or adhesive product according to an embodiment can be used to affix labels and the like. to a variety of packaging materials, including metal, glass and plastic. The packaging materials can be, for example, containers for food, beverages, or household chemicals, and these containers can be made of glass, metal, or plastic.

[0091] The adhesive composition or adhesive product can be used as adhesives, coatings, carriers, food additives, and the like. according to the composition and its characteristics.

[0092] When used as adhesives, the adhesive composition or adhesive product of the present invention can be applied to labels, sealants, wallpaper, cigarette paper, glue block toys, sand sculptures, food products, bath / kitchen detergents, spray animal ointments, exfoliators, hair fixatives, hair gels, soil stabilizers, water-based adhesives, paper reinforcements, corrugated board, zone adhesives, and the like. Soil stabilizers are used to remove fine dust such as sand dust or dust from factories.

[0093] When used as a coating agent, the adhesive composition or adhesive product of the present invention can be used for forest fire prevention, application to fruits and vegetables, cut flower surfaces, as colorants, anti-fouling pretreated coating agents etc. In the case of anti-fouling pretreated coating agents, when the composition is applied to a readily contaminated environment, contaminants can be removed therefrom by simply rinsing with water.

[0094] When used as carriers, the adhesive composition or adhesive product of the present invention can be used to protect forests from epidemics, prevent forest fires, bathroom air fresheners, disinfectants, agricultural materials, household chemicals, toys, etc. .P. Protecting a forest from epidemics can be, for example, preventing the spread of diseases such as pine stem nematode in forests, and disinfectants can be, for example, disinfectants against avian influenza and disinfectants against epizootic stomatitis. Agricultural supplies can include fertilizers, tape-based materials, and seed coatings.

[0095] When used as agricultural materials, the adhesive composition or adhesive product of the present invention can be used in seed coatings, plant adhesive tapes, insecticidal additives, fertilizer aids, natural pesticides, and the like. When used as a household product, the adhesive composition of the present invention can be added to paints to increase their adhesion strengths to paper without rinsing off, or added to food colors to produce edible paints for use by children. In other examples of household chemicals, the adhesive composition can also be used as a pre-decontamination agent. More specifically, contaminants can be quickly removed by spraying an adhesive composition according to the present invention onto a contaminated environment such as window panes, window frames, and automobiles, and then flushing the environment with water.

[0096] When used as carriers, the adhesive composition or adhesive product of the present invention can perform oxygen blocking, moisture blocking, oil resistance, and heat sealing functions. Thus, when used in coating layers of environmentally friendly food packaging materials, effects of preventing or retarding food decomposition and oxidation can be obtained while suppressing the penetration of external moisture. Also, when used as food additives, the adhesive composition or adhesive product of the present invention can be used in wheat gluten substitutes, jellies, syrup, biscuits, food colors, ice cream, and antifreezes.

USEFUL EFFECTS OF THE INVENTION

[0097] The adhesive composition according to an embodiment has the functions of water-removable adhesives, coating agents, and carriers. When the adhesive composition is used as a water-removable adhesive, the adhesive composition can easily peel off from the adhesive or substrate by the action of water to be easily removed therefrom. Thus, the adhesive material does not have a negative impact on the environment like a water-removable material.

MODE FOR CARRYING OUT THE INVENTION

[0098] Hereinafter, one or more embodiments of the present invention will be described in detail with reference to the following examples. These examples are not intended to limit the purpose and scope of one or more illustrative embodiments of the present invention.

[0099] Example 1. Evaluation of the stability of a composition containing lysine and various organic acids

[00100] Lysine, as the main amino acid, and various organic acids were mixed to prepare the compositions. Evaluated the stability of each composition (regardless of whether it formed precipitates).

[00101] A method of producing an adhesive composition containing lysine and alpha-ketoglutaric acid

[00102] 84.5 g of distilled water (DIW) was added to 100 g of an aqueous solution with 61.5 wt. % of the free form of L-lysine and the mixture was stirred at room temperature (25 ° C) for 30 minutes to dissolve the lysine. 61.47 g of alpha-ketoglutaric acid (aKG) was slowly added to the dissolved lysine with stirring for 1 hour at room temperature (25 ° C), and then the mixture was stirred at room temperature (RT) for 1 hour. Subsequently, after cooling the reaction mixture to room temperature (25 ° C), the reaction was stopped to obtain 245.97 g of an adhesive composition. The solids content of this composition was approximately 50 parts by weight based on 100 parts by weight of the composition, the molar ratio of lysine to alpha-ketoglutaric acid in the mixture was 1: 1, and deionized water was used as the solvent.

[00103] Compositions and were prepared in the same manner as described above using various types of organic acids. Compositions were prepared in the same manner as in Example 1, except that the organic acids shown in Table 1 below were used, respectively. The compositions were prepared in the same manner as described above using various types of organic acids.

[00104] Compositions were prepared in the same manner as in Example 1, except that the organic acids shown in Table 1 below were used respectively.

[00105]

[00106] The formation of precipitates in the compositions obtained in accordance with Table 1 was evaluated. Specifically, each of the compositions was applied to OPP film (Sam Young Chemical Co. Ltd.) with a thickness of 50 μm to a layer thickness of approximately 50 μm using a frame device for coating. After the film coated with the composition was kept at room temperature (25 ° C) at 60 ± 10% relative humidity for 14 days, its morphological changes were evaluated by detecting surface changes of each adhesive composition present on the OPP film. The analysis results are shown in Table 2 below.

[00107]

[00108] Referring to the results shown in Table 2, while precipitates did not form in the composition containing lysine and alpha-ketoglutaric acid, precipitates formed in the composition containing other organic acids and lysine, making it impossible to assess the adhesion. That is, in the case where the compositions were prepared by mixing lysine and various organic acids, it was confirmed that not all compositions exhibit non-precipitating adhesiveness.

[00109] Example 2. Evaluation of solubility depending on the solvent of the composition

[00110] Adhesive compositions containing lysine and alpha-ketoglutaric acid were prepared in the same manner as in example 1 (molar ratio of lysine to alpha-ketoglutaric acid = 1: 1 and solids content of 50 parts by weight). 25 g of the additional solvent shown in Table 3 below was added to 50 g of the resulting adhesive composition, and the mixture was stirred for 1 hour. After mixing, the solubility of the adhesive composition was determined under the action of each solvent. The types of solvent added and the results of evaluating the solubility of the adhesive composition with each solvent are shown in Table 3 below.

[00111]

[00112] Referring to Table 3, the adhesive composition according to the present invention was dissolved in an alcohol such as methanol used as a solvent, but did not dissolve in other organic solvents.

[00113]

[00114] Example 3. Analysis of the state, viscosity and initial adhesion of the adhesive composition depending on the molar ratio of lysine to alpha-ketoglutaric acid in the mixture

[00115] Analyzed the stability, viscosity and initial tack of the adhesive compositions of the present invention depending on the molar ratio of lysine to alpha-ketoglutaric acid contained in the adhesive compositions.

[00116] Adhesive compositions containing lysine and alpha-ketoglutaric acid were prepared in the same manner as in Example 1, except that the molar ratios of lysine to alpha-ketoglutaric acid were adjusted to 3: 1, 2.5: 1, 2 : 1, 1.5: 1, 1: 1, 1: 1.5, 1: 2, 1: 2.5 and 1: 3, respectively (assuming 50 parts by weight solids).

[00117]

[00118] (1) Assessment of stability

[00119] The stability of the adhesive compositions with different molar ratios was evaluated according to the following method. Approximately 1 g of each of the adhesive compositions was applied to a 5 cm diameter aluminum tray. The formation of deposits in the adhesive composition was then determined under the following drying conditions.

[00120] i) Drying conditions 1

[00121] The adhesive compositions were kept at room temperature (25 ° C) at a relative humidity of 60 ± 10% for 14 days to determine the formation of precipitates and changes in their surface.

[00122] ii) Drying Conditions 2

[00123] The adhesive composition was kept in an oven at 40 ° C for 48 hours to identify the formation of precipitation and changes in its surface.

[00124] (2) Estimation of viscosity

[00125] The viscosity was measured using a rotary viscometer (manufacturer: LAMYRHEOLOGY) at 25 ± 1 ° C using an LV-1 spindle at 60 rpm.

[00126] (3) Assessment of initial adhesion

[00127] Evaluated the initial adhesion of adhesive compositions in which there was no precipitation in the evaluation of stability. The initial adhesion of the adhesive compositions was measured with an Anton Paar, Co. rheometer. Ltd. and compared using the readings of a rheometer. A 25 mm SUS probe was contacted with each adhesive for 1 minute maintaining a gap of 0.01 mm, and then the force to detach the probe at the same speed was measured to quantify the instant initial adhesion.

[00128] The analysis results are shown in Table 4 below.

[00129]

[00130] * In Table 4, room temperature refers to drying condition 1 and oven refers to drying condition 2.

[00131] Referring to Table 4, precipitates formed in the adhesive composition when the molar ratio of lysine to alpha-ketoglutaric acid was in the range of 3: 1 to 2: 1.

[00132] While precipitates formed in the adhesive composition at a lysine to alpha-ketoglutaric acid molar ratio of 2: 1, precipitates did not form in the adhesive composition at a lysine to alpha-ketoglutaric acid molar ratio of 1.5: 1. For a more specific definition of the critical point, subgroups of adhesive compositions were obtained with molar ratios of lysine to alpha-ketoglutaric acid 2.0: 1, 1.9: 1, 1.8: 1, 1.7: 1, 1.6: 1 and 1 .5: 1 (assuming a solids content of 50 parts by weight). Then, their stability, toughness and initial tack were evaluated in the same way.

[00133] The analysis results are shown in Table 5 below.

[00134]

[00135] Referring to Table 5, while precipitation was formed when the molar ratio of lysine to alpha-ketoglutaric acid was in the range of 2: 1 to 1.8: 1, no precipitation was formed when the ratio of lysine to alpha-ketoglutaric acid ranged from 1.7: 1 to 1.5: 1.

[00136] Example 4. Analysis of the state, viscosity and initial adhesion of the adhesive composition depending on the solids content

[00137] Analyzed the state, viscosity and initial tack of the adhesive compositions of the present invention depending on the solids content.

[00138] 1) Evaluation of the dependence on solids content at a molar ratio of lysine to alpha-ketoglutaric acid 1: 1

[00139] Adhesive compositions containing lysine and alpha-ketoglutaric acid were prepared in the same manner as in example 1, except that the solids content of the adhesive compositions was adjusted to 10 wt. %, 20 wt. %, 30 wt. %, 40 wt. %, 50 wt. %, 60 wt. %, 70 wt. % and 75 wt. %, respectively (with a molar ratio of lysine to alpha-ketoglutaric acid 1: 1). The solids content was controlled by controlling the water content.

[00140] The condition, viscosity and initial tack of the compositions were evaluated in the same manner as in example 3. The results of the analysis are shown in table 6 below.

[00141]

[00142] Referring to Table 6, it was confirmed that precipitation was formed in the adhesive compositions when the solids content was in the range of 10 wt. % up to 70 wt. %.

[00143] For a more specific definition of the critical point received subgroups of adhesive compositions with a solids content of 65 wt. %, 66 wt. %, 67 wt. %, 68 wt. %, 69 wt. %, 70 wt. %, 71 wt. %, 72 wt. %, 73 wt. %, 74 wt. %, 75 wt. % and 76 wt. % in adhesive compositions (with a molar ratio of lysine to alpha-ketoglutaric acid 1: 1). Then, their stability, toughness and initial tack were evaluated in the same way. The analysis results are shown in Table 7 below.

[00144]

[00145] Referring to Table 7, while the adhesive compositions were maintained in a liquid state when the solids content was in the range of 65 wt. % up to 70 wt. % in the adhesive composition, precipitation was formed within two weeks at a solids content of 71 wt. % or more in the adhesive composition.

[00146] 2) Estimation versus solids content at a molar ratio of lysine to alpha-ketoglutaric acid 1: 2, 1: 3 or 2: 1

[00147] Assessed the formation of precipitates depending on the content of solids when changing the molar ratio of lysine to alpha-ketoglutaric acid.

[00148] Adhesive compositions containing lysine and alpha-ketoglutaric acid were prepared in the same manner as in example 1, except that the molar ratios of lysine to alpha-ketoglutaric acid were adjusted to 1: 2, 1: 3 and 2: 1 respectively. The water content was adjusted so that the solids content of the compositions at each molar ratio was 10 wt. %, 20 wt. %, 30 wt. %, 40 wt. %, 50 wt. %, 60 wt. % and 70 wt. % respectively. The stability of the compositions was evaluated in the same manner as in example 1. The results of the analysis are shown in table 8 below.

[00149]

[00150] Referring to Table 8, at molar ratios of lysine to alpha-ketoglutaric acid 1: 2 and 1: 3, no precipitation was formed, although the solids content varied from 10 wt. % up to 70 wt. %. However, regardless of the solids content, precipitates formed at a molar ratio of lysine to ketoglutaric acid of 2: 1.

[00151] That is, it can be confirmed that the molar ratio of lysine to alpha-ketoglutaric acid is the most important factor affecting the stability and adhesion strength of the adhesive composition according to the present invention. With the same molar ratio of lysine to alpha-ketoglutaric acid, the stability and adhesion strength of the adhesive composition is affected by the solids content.

[00152] Example 5. Comparison of initial adhesion and removability by water

[00153] Adhesion forces and water removability were compared between a conventional adhesive and an adhesive composition in accordance with the present invention.

[00154] An adhesive composition containing lysine and alpha-ketoglutaric acid was prepared in the same manner as in Example 1, except that the solids content was adjusted to 10 wt. % in the adhesive composition by adjusting the water content (with a molar ratio of lysine to alpha-ketoglutaric acid 1: 1)

[00155] A commercially available polyvinyl alcohol adhesive (PVA 088-50, Qingdao Sanhuan Colorchem CO.LTD.) Was prepared and the solids content was adjusted to 10 wt. % by controlling the water content (hereinafter referred to in this document as control 1).

[00156] The viscosity and initial tack of the adhesive composition according to the present invention (solids content: 10 wt.%) And control 1 were evaluated in the same manner as in example 3.

[00157] The water removability of the adhesive composition according to the present invention (solids content 10 wt.%) And control 1 were evaluated. The water removability was evaluated in accordance with the following method.

[00158] The adhesive composition according to the present invention was applied to a PET film at a layer thickness of 50-60 µm and dried at 40 ° C for 30 minutes. The material obtained after drying was cut into 25 mm × 25 mm sections and attached to stainless steel (SUS304) by pressing five times at a pressure of 2 kgf using a hand roller to obtain samples. The PVA-based adhesive was applied to the PET film at a layer thickness of 50-60 μm, cut into 25 mm × 25 mm sections, attached to stainless steel (SUS304) by pressing five times at a pressure of 2 kgf using a hand roller to obtain a sample.

[00159] Each of the samples was completely immersed in distilled water (DIW) at room temperature, atmospheric pressure and neutral pH and stirred at 200 rpm using a stirrer. The state of the samples was determined: i) after 1 hour or ii) after 24 hours. Then, the time periods were measured during which the samples in accordance with the present invention and the adhesive, which is control 1, were completely removed to assess the removability of the samples by water.

[00160] The analysis results are shown in Table 9 below.

[00161]

[00162] Referring to Table 9, the adhesive composition according to the present invention showed an initial tack equal to or greater than that of the PVA based adhesive composition (control 1), and peeled off rapidly in comparison to water. In contrast, the PVA-based adhesive composition dissolved in water after 24 hours, but partially dissolved in water after 1 hour.

[00163] That is, the adhesive composition according to the present invention has a similar or stronger adhesion strength and much better water removability than a conventional adhesive, and thus the use of the adhesive composition according to the present invention in various fields of technology can be expected.

[00164] Example 6 Evaluation of Initial Tack and Water Removability as a Function of Solvent

[00165] Adhesive compositions containing lysine and alpha-ketoglutaric acid were prepared in the same manner as in Example 1 (6-1 to 6-3 below), except that the molar ratios of lysine to alpha-ketoglutaric acid were adjusted to 1.5: 1, 1: 1 and 1: 1.5, respectively (assuming 50 parts by weight solids).

[00166] Adhesive compositions containing lysine and alpha-ketoglutaric acid were prepared in the same manner as in Example 1 (6-4 to 6-6 below), except that the molar ratios of lysine to alpha-ketoglutaric acid were adjusted to 1.5: 1, 1: 1 and 1: 1.5, respectively, and used a mixed solvent of deionized water and methanol at a weight ratio of 1: 1 (with a solids content of 50 parts by weight).

[00167] As a control, a commercially available acrylic adhesive (K901, Hansung P&I, hereinafter referred to as control 2, at 59 wt% solids) was prepared. The peel strength and water removability of each of the adhesive compositions was evaluated according to the following methods, and the analysis results are shown in Table 10 below.

[00168] 1) Removability by water

[00169] Each of the obtained adhesive compositions in accordance with the present invention and control 2 were applied to a PET film at a layer thickness of 50-60 µm and dried at 40 ° C for 30 minutes.

[00170] The materials obtained after drying were cut into 25 mm × 25 mm sections and attached to stainless steel (SUS304) by pressing five times at a pressure of 2 kgf using a hand roller to obtain samples.

[00171] Each of the samples was completely immersed in distilled water (DIW) at room temperature, atmospheric pressure and neutral pH and stirred at 200 rpm using a stirrer. The state of the samples was determined: i) after 1 hour or ii) after 24 hours.

[00172]

[00173] Referring to Table 10, the adhesive product obtained using the adhesive composition according to the present invention peeled off within 1 hour after immersion in water. In addition, it was confirmed that when alcohol and water were used as solvents, the initial adhesion was also increased. These results could be obtained because the adhesive composition containing the mixed solvent has a lower contact angle than the composition containing only deionized water and better coating properties on the substrate. Although the adhesive composition according to the present invention showed a similar initial tack, even at a lower solids content compared to a conventional acrylic adhesive (control 2). However, the acrylic adhesive did not dissolve in water even after 24 hours.

[00174] Example 7. Analysis of the composition of the adhesive composition depending on the reaction time and temperature

[00175] Analyzed the ratio of the components in the adhesive compositions depending on the reaction time.

[00176] 1) Getting at 40 ° C: 61.95 g of DIW was added to 100 g of an aqueous solution with 54 wt. % of the free form of lysine and the mixture was stirred at room temperature (25 ° C, T1) for 30 minutes.

[00177] The resulting dissolved material was slowly stirred while simultaneously adding 53.97 g of alpha-ketoglutaric acid at 40 ° C (T2) for 12 hours to obtain an adhesive composition (solids content 50 wt.% And molar ratio of lysine to alpha -ketoglutaric acid in a mixture = 1: 1). Analysis of the composition of the adhesive composition was carried out every 3 hours.

[00178] 2) Preparation at room temperature (RT): An adhesive composition was prepared in the same manner as method 1) above, except that T2 was changed to RT. Analysis of the composition of the adhesive composition was carried out every 3 hours.

[00179] Compositional analysis was performed on the resulting compositions by high performance liquid chromatography (HPLC).

[00180] The analysis results are shown in Table 11 below.

[00181]

[00182] Referring to Table 11, it was confirmed that the amount of lysine and alpha-ketoglutaric acid in the composition gradually decreased over time when the composition was prepared at 40 ° C.

[00183] In contrast, when the composition was prepared at room temperature, although the amounts of lysine and alpha-ketoglutaric acid decreased over time, the rate of decrease decreased compared to the case when the composition was prepared at 40 ° C. [00184] Therefore, it can be confirmed that at 40 ° C there are side reactions which cause hardening.

[00185] It should be understood that the embodiments described herein are to be considered in a descriptive sense only and not for purposes of limitation. The description of features or aspects within each embodiment is generally to be construed as appropriate to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to numerical values, those skilled in the art will appreciate that various changes in shape and detail may be made therein without departing from the spirit and scope of the present invention as defined in the following claims.

Claims (8)

1. An adhesive composition containing lysine, alpha-ketoglutaric acid and water, where lysine and alpha-ketoglutaric acid are present in the form of an aqueous salt solution and do not form precipitates in the adhesive composition, where the molar ratio of lysine and alpha-ketoglutaric acid is in the range from 1 , 7: 1 to 1: 3 and where the sum of the contents of lysine and alpha-ketoglutaric acid in the adhesive composition is from 0.1 to 70 parts by weight, based on the total weight of the adhesive composition. 2. The adhesive composition according to claim 1, wherein the molar ratio of lysine and alpha-ketoglutaric acid in the mixture is adjusted so that no precipitates of lysine and alpha-ketoglutaric acid are formed in the adhesive composition. 3. An adhesive composition according to claim 1, further comprising at least one solvent selected from a primary alcohol, a polyhydric alcohol, a diol and a triol. 4. The adhesive composition according to claim 3, where the solvent provides at least one monohydric alcohol selected from methanol, ethanol, propan-2-ol, butan-1-ol, pentan-1-ol and hexadecan-1-ol; at least one polyhydric alcohol selected from ethane-1,2-diol, propane-1,2-diol, propane-1,2,3-triol, butane-1,3-diol, butane-1,2,3 , 4-tetraol, pentane-1,2,3,4,5-pentol, hexane-1,2,3,4,5,6-hexole and heptane-1,2,3,4,5,6,7 -heptol; at least one unsaturated aliphatic alcohol selected from prop-2-en-1-ol, 3,7-dimethylocta-2,6-diene-1-ol, and prop-2-yn-1-ol; at least one alicyclic alcohol selected from cyclohexane-1,2,3,4,5,6-hexole and 2- (2-propyl) -5-methylcyclohexan-1-ol; or a mixture thereof. 5. The adhesive composition according to claim 1, wherein when the adhesive composition is stored at a temperature of -18 ° C or higher to less than 40 ° C for 14 days or longer, no precipitates are formed in the adhesive composition. 6. A method for producing an adhesive composition, the method comprising: mixing lysine, alpha-ketoglutaric acid and water to obtain a mixture and stirring the mixture at a temperature of less than 40 ° C, while the corresponding lysine content, alpha-ketoglutaric acid content and water content are controlled in such a way in such a way that precipitates of lysine and alpha-ketoglutaric acid in the adhesive composition are not formed, where the molar ratio of lysine and alpha-ketoglutaric acid is in the range from 1.7: 1 to 1: 3 and where the sum of the contents of lysine and alpha-ketoglutaric acid is from 0.1 to 70 parts by weight based on the total weight of the adhesive composition. 7. The method of claim 6, wherein the mixture further comprises at least one solvent selected from a primary alcohol, a polyhydric alcohol, a diol, and a triol. 8. An adhesive product containing an adhesive composition according to any one of claims. 1-5.